Chapter 3 GIS Operations

By design, GeoDa is primarily focused on analysis and is not intended to be a geographic information system (GIS). However, over the years and in response to user requests, a range of spatial data manipulation functions have been incorporated. These include efficient treatment of projections, conversion between points and polygons, the computation of a minimum spanning tree, spatial aggregation and spatial join through multi-layer support. These functions are not intended to replace the range of operations that can be carried out in a proper GIS, but rather serve as an alternative for those without access to or familiarity with a GIS.

In this chapter, I present a quick overview of this functionality, again primarily aimed at novices in the field. Readers familiar with GIS operations can skim over the material to check on how these elementary spatial data manipulations are handled in GeoDa. The discussion is limited to the essentials. More extensive treatments are offered in standard GIS texts, such as Law and Collins (2018), Brunsdon and Comber (2019), Shellito (2020), and Madry (2021), among many others.

The various operations will be again be illustrated with the Chicago Carjackings data set from the Sample Data, as well as with the Community Area boundary layer from the GeoDaCenter sample data site, Chicago_community_areas.shp.